As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW WAS PERFORMING NIGHT PROFICIENCY FLIGHT. UPON 1ST LANDING, AIRCRAFT TAXIED AROUND FOR SECOND TAKEOFF. ON POWER UP FOR TAKEOFF ROLL, THE RIGHT ENGINE THRUST REVERSER HAD AN UNCOMMANDED DEPLOYMENT. CREW ABORTED TAKEOFF. RIGHT REVERSER WOULD NOT STOW. ACFT RETURNED TO HANGAR. TROUBLESHOT REVERSER SYSTEM. FOUND RT T/R SELECTOR VALVE DEFECTIVE. THE SAFETY FEATURE TO PREVENT THE THROTTLE FROM BEING ADVANCED IS CONTROLLED BY THE SELECTOR VALVE WAS ALSO INOPERABLE.